The referenced application Ser. No. 346,034, filed Jan. 28, 1982, Dobler, refiled as Ser. No. 597,588, Apr. 10, 1984 assigned to the assignee of the present application (corresponding to the published international application WO No. 82/00520) describes a pressure sensor to determine knocking, or a tendency to knock of an internal combustion engine, by placing a pressure-sensitive resistor into the combustion chamber of the engine. The pressure sensor resistor can be formed as a layer-like resistor or as a wire-wound resistor; if a wire-wound resistor, it can be wound as a spiral positioned within the breathing space of a sparkplug, that is, in the space between the central insulator and the inner surface of the wall of the metal housing of the sparkplug. A layer-like resistor may also be used applied, for example, to the outside of a ceramic tube which is heated to pre-heat the combustion chamber of diesel engines.